438 PROCEEDINGS OF THE ACADEMY OF [Oct.^ 



and anterior rays apparently well elevated. Anal inserted just 

 behind base of last dorsal ray, also nearer base of caudal than origin of 

 pectoral, and anterior rays apparently elongated. Caudal forked, 

 lobes apparently pointed. Pectoral small, evidently not attaining 

 ventral(?). Ventral inserted a little before origin of dorsal or nearlj- 

 midway between origin of pectoral and that of anal, and perhaps 

 reaching(?) latter. 



Color in alcohol brownish, back darker, and side evidently silvered. 

 Fins brownish, except base of caudal which is largely blackish. No 

 trace of humeral blotch. Iris brownish. 



Length lyf inches (caudal damaged). 



Type, No. 21,435, A. N. S. P. Near Pebas, Peru. Prof. J. Orton. 

 CoU. of 1877. Prof. E. D. Cope. Also paratype, No. 21,436, A. N. S. 

 P., with same data. Both in poor preservation. 



This form is very close to Astyanax agassizii (Steindachner), differing, 

 as Cope long pointed out, in the longer body. It also has fewer anal 

 radii. 



(Named for Atahualpa, among the last of the vmfortunate Incas of 

 Peru, who was strangled by the Spaniards at Cajamarca, August 29, 

 1533.) 



Astyanax oligolepis (Gunther). Fig. 37. 



Width of head If in its length; interorbital space 2^. Body com- 

 pressed. Predorsal region with a median rounded ridge, postdorsal and 

 pre ventral regions rounded, and postventral region a little tren- 

 chant. Head compressed. Snout broad with convex surface. 

 Lips rather thin. Teeth as usual, with a small one at base of 

 maxillary. Tongue a little pointed and rather attenuated. Inter- 

 orbital space broadly convex. Gill-opening forward opposite end 

 of maxillary. Rakers 9 + 11, about | length of filaments which 

 are f of eye. Scales with several radiating striae. Tubes in 

 lateral line simple. Color in alcohol brownish, evidently discolored 

 greenish. About 8 or 9 longitudinal dark streaks, each one following in 

 courses of scales at their junctions above and below. Fins more or 

 less plain brownish, and dorsal and caudal perhaps a little darker. Iris 

 dull orange-brown. Length 3yV inches. Peruvian Amazon. Prof. 

 J. Orton Coll. Also 2 other examples. 



The above account agrees largely with Dr. Giinther's, though the eye 

 is larger and the maxillary extends to the front margin of the eye in 

 his examples. In mine there are indistinct traces of both caudal and 

 humeral spots which I suspect have more or less faded. 



